[PATCH v4] gpio: mcp23s08: convert driver to DT
Lars Poeschel
larsi at wh2.tu-dresden.de
Thu Apr 4 21:02:02 EST 2013
From: Lars Poeschel <poeschel at lemonage.de>
This converts the mcp23s08 driver to be able to be used with device
tree.
There is a "spi-present-mask" device tree property, that allows to
use multiple of this spi chips on the same chipselect.
Signed-off-by: Lars Poeschel <poeschel at lemonage.de>
---
v4:
- removed the ability to specify the pullup from device tree
- updated binding doc
v3:
- removed mcp,chips device tree property in favour of a
mcp,spi-present-mask and a flag for the pullup of every gpio
- seperated the match table. Now there is one for i2c and one for spi
- do the of reading stuff on stack of the probe function - no devm
any more
v2:
- squashed booth patches together
- fixed build warning, when CONFIG_OF is not defined
- use of_match_ptr macro for of_match_table
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
diff --git a/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
new file mode 100644
index 0000000..629d0ef
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
@@ -0,0 +1,47 @@
+Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for
+8-/16-bit I/O expander with serial interface (I2C/SPI)
+
+Required properties:
+- compatible : Should be
+ - "mcp,mcp23s08" for 8 GPIO SPI version
+ - "mcp,mcp23s17" for 16 GPIO SPI version
+ - "mcp,mcp23008" for 8 GPIO I2C version or
+ - "mcp,mcp23017" for 16 GPIO I2C version of the chip
+- #gpio-cells : Should be two.
+ - first cell is the pin number
+ - second cell is used to specify flags. Flags are currently unused.
+- gpio-controller : Marks the device node as a GPIO controller.
+- reg : For an address on its bus. I2C uses this a the I2C address of the chip.
+ SPI uses this to specify the chipselect line which the chip is
+ connected to. The driver and the SPI variant of the chip support
+ multiple chips on the same chipselect. Have a look at
+ mcp,spi-present-mask below.
+
+Required device specific properties (only for SPI chips):
+- mcp,spi-present-mask : This is a present flag, that makes only sense for SPI
+ chips - as the name suggests. Multiple SPI chips can share the same
+ SPI chipselect. Set a bit in bit0-7 in this mask to 1 if there is a
+ chip connected with the corresponding spi address set. For example if
+ you have a chip with address 3 connected, you have to set bit3 to 1,
+ which is 0x08. mcp23s08 chip variant only supports bits 0-3. It is not
+ possible to mix mcp23s08 and mcp23s17 on the same chipselect. Set at
+ least one bit to 1 for SPI chips.
+- spi-max-frequency = The maximum frequency this chip is able to handle
+
+Example I2C:
+gpiom1: gpio at 20 {
+ compatible = "mcp,mcp23017";
+ gpio-controller;
+ #gpio-cells = <2>;
+ reg = <0x20>;
+};
+
+Example SPI:
+gpiom1: gpio at 0 {
+ compatible = "mcp,mcp23s17";
+ gpio-controller;
+ #gpio-cells = <2>;
+ spi-present-mask = <0x01>;
+ reg = <0>;
+ spi-max-frequency = <1000000>;
+};
diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index 3cea0ea..6a4470b 100644
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -12,6 +12,8 @@
#include <linux/spi/mcp23s08.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
/**
* MCP types supported by driver
@@ -383,6 +385,10 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
mcp->chip.direction_output = mcp23s08_direction_output;
mcp->chip.set = mcp23s08_set;
mcp->chip.dbg_show = mcp23s08_dbg_show;
+#ifdef CONFIG_OF
+ mcp->chip.of_gpio_n_cells = 2;
+ mcp->chip.of_node = dev->of_node;
+#endif
switch (type) {
#ifdef CONFIG_SPI_MASTER
@@ -473,6 +479,35 @@ fail:
/*----------------------------------------------------------------------*/
+#ifdef CONFIG_OF
+#ifdef CONFIG_SPI_MASTER
+static struct of_device_id mcp23s08_spi_of_match[] = {
+ {
+ .compatible = "mcp,mcp23s08", .data = (void *) MCP_TYPE_S08,
+ },
+ {
+ .compatible = "mcp,mcp23s17", .data = (void *) MCP_TYPE_S17,
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
+#endif
+
+#if IS_ENABLED(CONFIG_I2C)
+static struct of_device_id mcp23s08_i2c_of_match[] = {
+ {
+ .compatible = "mcp,mcp23008", .data = (void *) MCP_TYPE_008,
+ },
+ {
+ .compatible = "mcp,mcp23017", .data = (void *) MCP_TYPE_017,
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, mcp23s08_i2c_of_match);
+#endif
+#endif /* CONFIG_OF */
+
+
#if IS_ENABLED(CONFIG_I2C)
static int mcp230xx_probe(struct i2c_client *client,
@@ -480,12 +515,23 @@ static int mcp230xx_probe(struct i2c_client *client,
{
struct mcp23s08_platform_data *pdata;
struct mcp23s08 *mcp;
- int status;
-
- pdata = client->dev.platform_data;
- if (!pdata || !gpio_is_valid(pdata->base)) {
- dev_dbg(&client->dev, "invalid or missing platform data\n");
- return -EINVAL;
+ int status, base, pullups;
+ const struct of_device_id *match;
+
+ match = of_match_device(of_match_ptr(mcp23s08_i2c_of_match),
+ &client->dev);
+ if (match) {
+ base = -1;
+ pullups = 0;
+ } else {
+ pdata = client->dev.platform_data;
+ if (!pdata || !gpio_is_valid(pdata->base)) {
+ dev_dbg(&client->dev,
+ "invalid or missing platform data\n");
+ return -EINVAL;
+ }
+ base = pdata->base;
+ pullups = pdata->chip[0].pullups;
}
mcp = kzalloc(sizeof *mcp, GFP_KERNEL);
@@ -493,8 +539,7 @@ static int mcp230xx_probe(struct i2c_client *client,
return -ENOMEM;
status = mcp23s08_probe_one(mcp, &client->dev, client, client->addr,
- id->driver_data, pdata->base,
- pdata->chip[0].pullups);
+ id->driver_data, base, pullups);
if (status)
goto fail;
@@ -531,6 +576,7 @@ static struct i2c_driver mcp230xx_driver = {
.driver = {
.name = "mcp230xx",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(mcp23s08_i2c_of_match),
},
.probe = mcp230xx_probe,
.remove = mcp230xx_remove,
@@ -565,28 +611,55 @@ static int mcp23s08_probe(struct spi_device *spi)
unsigned chips = 0;
struct mcp23s08_driver_data *data;
int status, type;
- unsigned base;
-
- type = spi_get_device_id(spi)->driver_data;
-
- pdata = spi->dev.platform_data;
- if (!pdata || !gpio_is_valid(pdata->base)) {
- dev_dbg(&spi->dev, "invalid or missing platform data\n");
- return -EINVAL;
- }
+ unsigned base = -1,
+ ngpio = 0,
+ pullups[ARRAY_SIZE(pdata->chip)];
+ const struct of_device_id *match;
+ u32 spi_present_mask = 0;
+
+ match = of_match_device(of_match_ptr(mcp23s08_spi_of_match), &spi->dev);
+ if (match) {
+ type = (int)match->data;
+ status = of_property_read_u32(spi->dev.of_node,
+ "mcp,spi-present-mask", &spi_present_mask);
+ if (status) {
+ dev_err(&spi->dev, "DT has no spi-present-mask\n");
+ return -ENODEV;
+ }
+ if ((spi_present_mask <= 0) || (spi_present_mask >= 256)) {
+ dev_err(&spi->dev, "invalid spi-present-mask\n");
+ return -ENODEV;
+ }
- for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
- if (!pdata->chip[addr].is_present)
- continue;
- chips++;
- if ((type == MCP_TYPE_S08) && (addr > 3)) {
- dev_err(&spi->dev,
- "mcp23s08 only supports address 0..3\n");
+ for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++)
+ pullups[addr] = 0;
+ } else {
+ type = spi_get_device_id(spi)->driver_data;
+ pdata = spi->dev.platform_data;
+ if (!pdata || !gpio_is_valid(pdata->base)) {
+ dev_dbg(&spi->dev,
+ "invalid or missing platform data\n");
return -EINVAL;
}
+
+ for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
+ if (!pdata->chip[addr].is_present)
+ continue;
+ chips++;
+ if ((type == MCP_TYPE_S08) && (addr > 3)) {
+ dev_err(&spi->dev,
+ "mcp23s08 only supports address 0..3\n");
+ return -EINVAL;
+ }
+ spi_present_mask |= 1 << addr;
+ pullups[addr] = pdata->chip[addr].pullups;
+ }
+
+ if (!chips)
+ return -ENODEV;
+
+ base = pdata->base;
}
- if (!chips)
- return -ENODEV;
data = kzalloc(sizeof *data + chips * sizeof(struct mcp23s08),
GFP_KERNEL);
@@ -594,21 +667,22 @@ static int mcp23s08_probe(struct spi_device *spi)
return -ENOMEM;
spi_set_drvdata(spi, data);
- base = pdata->base;
for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
- if (!pdata->chip[addr].is_present)
+ if (!(spi_present_mask & (1 << addr)))
continue;
chips--;
data->mcp[addr] = &data->chip[chips];
status = mcp23s08_probe_one(data->mcp[addr], &spi->dev, spi,
0x40 | (addr << 1), type, base,
- pdata->chip[addr].pullups);
+ pullups[addr]);
if (status < 0)
goto fail;
- base += (type == MCP_TYPE_S17) ? 16 : 8;
+ if (base != -1)
+ base += (type == MCP_TYPE_S17) ? 16 : 8;
+ ngpio += (type == MCP_TYPE_S17) ? 16 : 8;
}
- data->ngpio = base - pdata->base;
+ data->ngpio = ngpio;
/* NOTE: these chips have a relatively sane IRQ framework, with
* per-signal masking and level/edge triggering. It's not yet
@@ -668,6 +742,7 @@ static struct spi_driver mcp23s08_driver = {
.driver = {
.name = "mcp23s08",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(mcp23s08_spi_of_match),
},
};
--
1.7.10.4
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